This invention relates generally to fasteners which are employed to fasten roofing membrane material or roofing insulation to a roof deck. More particularly, this invention relates to fasteners which upon installation are expandable to enhance the fastening integrity.
In roofing systems to which the invention has particular applicability, fasteners are conventionally employed to secure roof insulation or roofing membrane material to the deck of the roof. The roof deck is typically formed of cementitious wood fiber, gypsum or lightweight concrete. The membrane material and insulation is typically configured in large sheets. Multiple fasteners are inserted through the membrane or insulation and anchored in the deck in a manner which ensures that the roof material will remain fastened in place.